Elucidation of the use of sea area by breeding Japanese murrelet within a proposed wind power generation site ―Research Group of Japanese Murrelets at Mikomoto Island―

Abstract

The Japanese murrelet is a seabird that lives only in the seas around Japan, and is designated as an endangered species. Mikomotojima Island is a valuable breeding ground for this species, and in the surrounding areas, plans for the construction of an offshore wind farm have been announced. In this study, we attached GPS loggers to five Japanese murrelets and obtained 20-50 hours of location records from five individuals and 41-107 dive records from four of them. The logger-equipped individuals mainly used waters shallower than 20m depth on the west side of the island. The core area of habitat ranged from 3.2 to 77.5 km² (average 35.93 km²). Dives were conducted during the daytime, with a mean depth of 3.0-4.0m and a mean dive duration of 8.2-11.2s. In combination with the results of previous studies, the area used by this species overlaps with the southeastern part of the proposed offshore wind farm construction site, and it is thought that this species, which forages during the day for prey distributed in shallow water, will be greatly affected by the construction site.